But how many bacteria actually transfer in five seconds? In 2007, my lab at Clemson University published a study in the Journal of Applied Microbiology. We wanted to know if the length of time food is in contact with a contaminated surface affected the rate of transfer of bacteria to the food. To find out, we introduced bacteria to squares of tile, carpet or wood. Five minutes after that, we placed either bacon or bread on the surface for5, 30 or 60 seconds, and then measured the number of bacteria transferred to the food. We repeated this exact procedure after the bacteria had been on the surface for 2,4,8 and 24 hours.